Thermogravimetric characteristics and thermokinetic analysis on PM emission of diesel engine with catalyst

An experiment on oxidation features of diesel engine exhaust particulate matter added by catalysts Co3O4 and CeO2 in the atmosphere of O2 concentration of 10.3% was carried out using thermogravimetric analysis method.Thereafter the activation energy of oxidation reaction of the soot in particles was calculated based on Flynn-Wall-Ozawa algorithm. Results show that the weight loss of exhaust particles is mainly caused by the volatilization and oxidation of SOF in low temperature zone and the oxidation of soot in high temperature zone, the percents of the two temperature zones are approximately 32% and 63%.The addition of catalysts mainly promotes the soot oxidation process and has little effect on the SOF volatilization and oxidation. Taking the particle thermogravimetric characteristics without catalyst as a baseline, with the increasing trend of catalyst (Co3O4 and CeO2) fractions of 10%, 15% and 20%, temperatures for ignition, peak weight loss rate and burnout of the soot oxidation decrease and the peak weight loss rate increases at the same time.After adding Co3O4 and CeO2, the peak weight loss rates are below and above the basic reference separately.Catalysts significantly reduce the particle oxidation activation energy, thus with the additions of 10% and 15% fractions of Co3O4, the particle oxidation activation energy are reduced from 215.8 kJ/mol to 190.2 kJ/mol and 167.8 kJ/mol separately.